EP3337301A1 - Method for manufacturing a led module - Google Patents

Abstract

A method of making an LED module (400), the method comprising:
- Attaching conductor surfaces (440) with a self-adhesive layer (430) on a support member (410), and
Mounting an LED (460) on the conductor surfaces,
wherein the fixing of the conductor surfaces is performed by an SMD placement machine

Description

The present invention relates to a method for producing an LED module. The invention further relates to an LED module.

Printed Circuit Boards (PCB) are generally needed to assemble electronic components, particularly LEDs, into an electrical circuit. Different electronic circuits require different conductor tracks, the so-called layout. In order to improve or update an electronic circuit, you often need a new layout and thus a new circuit board. LED modules are usually connected thermally and mechanically in the luminaire housings or on the respective luminaire carriers.

1. 1. Bohren
2. 2. Durchkontaktieren (bei doppelseitigen Leiterplatten)
3. 3. Fotoresist laminieren
4. 4. Belichten
5. 5. Entwickeln
6. 6. Ätzen
7. 7. Spülen
8. 8. Trocknen

The most common way of producing a printed circuit board for an LED module is the photochemical process comprising the following production steps:

1. 1. Drilling
2. 2. Through-hole (with double-sided printed circuit boards)
3. 3. Laminate photoresist
4. 4. Exposure
5. 5. Develop
6. 6. Etching
7. 7. Rinse
8. 8. Dry

If a solder resist is needed, the job follows as an optional 9th step. All copper conductors are coated with lacquer and the copper surfaces, which are later soldered to the LED, are partially painted.

The object of the present invention is to provide a method for the production of LED modules, which simplifies the production and / or enables better thermal or mechanical properties of the LED module.

The object is achieved by a method according to claim 1.

• Befestigen von Leiterflächen mit einer selbstklebenden Schicht auf einem Trägerelement, und
• Befestigen einer LED auf den Leiterflächen,

wobei das Befestigen der Leiterflächen durch einen SMD-Bestückungsautomaten erfolgt.Accordingly, a method of manufacturing an LED module comprises:

• Attaching conductor surfaces with a self-adhesive layer on a support element, and
• Fixing an LED on the conductor surfaces,

wherein the fixing of the conductor surfaces is performed by an SMD placement machine.

This method has the advantage that the conductor surfaces do not arise as (not etched away) remainder of a full-surface coating, but that only the conductor surfaces are selectively applied. This is particularly advantageous when the conductor surfaces are of a certain thickness, e.g. greater than 0.05 mm, in particular greater than 0.1 mm, to be performed in order to achieve a sufficient thermal conductivity and thus to allow a better heat dissipation.

According to one embodiment, it is provided that the fastening of the conductor surfaces comprises applying the self-adhesive layer to the conductor surfaces and subsequently fastening the conductor surface with the self-adhesive layer to the carrier element.

This has the advantage that only as much adhesive must be used as the conductor surfaces must be attached.

According to a further embodiment, it is provided that the fastening of the conductor surfaces comprises applying the self-adhesive layer to the carrier element and then fastening the conductor surfaces to the carrier element.

In this embodiment, if necessary, a greater need for adhesive is given, but the manufacturing process can be simplified.

Preferably, a double-sided, insulating adhesive tape is glued to a carrier element serving as steel or aluminum sheet and then placed untreated copper pads as a conductor surfaces on the tape.

The self-adhesive layer may comprise an electrically insulating material.

According to a preferred embodiment, the conductor surfaces have a thickness of between 0.07 mm and 0.7 mm. Experiments have shown that this good thermal conductivity and at the same time still good handling of the conductor surfaces can be achieved in the SMD placement machine.

According to one embodiment, the length and width of the conductor surfaces are greater than the length and width of the LED. This has the advantage that the conductor surface can serve as a heat sink for the LED.

According to a preferred embodiment, the self-adhesive layer comprises polysiloxane adhesive, acrylate adhesive and / or a Polyimide adhesive tape with a thickness of 5 .mu.m to 100 .mu.m, preferably with a thickness of 10 .mu.m to 50 .mu.m.

Experiments have shown that the conductor surfaces can thus be fastened particularly well to the carrier element.

• Erfassen von Abmessungen der Leiterflächen und
• basierend auf den Abmessungen, Berechnen einer Platzierung der Leiterflächen, um ein vorgegebenes Layout zu realisieren.

According to a preferred embodiment, the method further comprises:

• Capture dimensions of the conductor surfaces and
• based on the dimensions, calculating a placement of the conductor surfaces to realize a given layout.

The dimensions of the conductor surfaces may be e.g. stored in a database. The layout may e.g. be entered by a user. The method may include determining which combinations of conductor surfaces the layout thus specified can be realized. If different combinations of conductor surfaces come into consideration, the combination can be selected with which the layout can be realized with as few conductor surfaces as possible.

Thus, even complicated layouts can be automatically realized from a limited number of conductor surfaces of different geometries.

According to a preferred embodiment, the method further comprises that the SMD placement machine provides the conductor surfaces with the self-adhesive layer. Thus, the SMD placement machines conductor surfaces can be provided without self-adhesive layer as a starting material and automatically provided in the SMD placement machine with the self-adhesive layer.

According to a preferred embodiment, the conductor surfaces are supplied via a bulk material feed, a linear feed and / or a roll as taped starting material.

According to a preferred embodiment, it is provided that the carrier element is electrically conductive on the side facing the conductor surfaces and the conductor surfaces have an insulation layer, the insulation layer preferably being adjacent to the self-adhesive layer.

According to a preferred embodiment, it is provided that the carrier element comprises a plate made of composite plastic, glass and / or sheet metal.

The sheet may be painted or unpainted and e.g. Aluminum, steel and / or galvanized steel.

According to a preferred embodiment, it is provided that the conductor surfaces comprise metal, in particular copper.

Likewise, the conductor surface may also include tinplate.

• Befestigen von Leiterflächen mit einer selbstklebenden Schicht auf einem Trägerelement, und
• Befestigen einer LED auf den Leiterflächen,

wobei das Befestigen der Leiterflächen durch einen SMD-Bestückungsautomaten erfolgt.The invention further relates to an LED module, producible with the steps:

• Attaching conductor surfaces with a self-adhesive layer on a support element, and
• Fixing an LED on the conductor surfaces,

wherein the fixing of the conductor surfaces is performed by an SMD placement machine.

According to one embodiment of the LED module is provided that the circuit board is a housing of the LED module.

The LED module may be part of a luminaire or comprise the entire luminaire.

Since linear as well as flat LED modules often consist of several LED chains, layouts are often very simple to design, without the need for many different interconnect structures. Since the support member can be made relatively free, the support member can simultaneously represent the housing of the lamp and record a lighting cover.

Figur 1

zeigt eine Draufsicht auf eine Leiterfläche,

Figur 2

zeigte eine Seitenansicht einer Leiterfläche,

Figur 3

zeigt eine Draufsicht auf ein LED-Modul und

Figur 4

zeigt eine Seitenansicht eines LED-Moduls.

Further features and advantages of the present invention will become apparent from the following description of a preferred embodiment, taken in conjunction with the figures. The figures show the following:

FIG. 1

shows a plan view of a conductor surface,

FIG. 2

showed a side view of a conductor surface,

FIG. 3

shows a plan view of an LED module and

FIG. 4

shows a side view of an LED module.

FIG. 1 shows a plan view of a conductor surface 100. In this case, a first portion 110 of a bare copper surface and a provided with Lötstopplack second region 120 is visible.

FIG. 2 shows a side view of a conductor surface 200. The conductor surface 200 includes a first layer 210 of a self-adhesive material, a second layer of a dielectric 220, a third layer 230 of copper and a fourth layer 240 of solder resist.

• der optische Reflektionsgrad erhöht,
• die Materialbeständigkeit und der Korrosionsschutz verbessert und
• die Ausrichtung der SMD-Bauteile im SMT- und Lötprozess verbessert werden.

Through the solder mask can

• the optical reflectance increases,
• improves the material resistance and the corrosion protection and
• The alignment of the SMD components in the SMT and soldering process can be improved.

• Lackierverfahren (beispielsweise Siebdruck)
• Klebeband mit Aussparungen für die bestückten Bauteile (Beispiel: LEDs, Widerstände, Klemmen, ... )
• Die oben beschriebenen kupferkaschierten Labels können über der vollflächigen Kupferschicht teilweise mit Lötstopplack/Lötstopplackalternative (1d) überdeckt ausgeführt sein

The application of the solder mask can be realized by the following methods:

• Painting process (eg screen printing)
• Adhesive tape with recesses for the assembled components (example: LEDs, resistors, terminals, ...)
• The copper-clad labels described above may be partially covered with solder mask / solder resist alternative (1d) over the full-area copper layer

The conductor surfaces 100, 200 may be parts of a printed circuit board of an LED module. This LED module can be created by using an SMD placement machine to place the conductor surfaces, which form the layout of the PCB, in the form of individual pads of different geometry on a support element.

In this case, the placement machine conductor surfaces in the form of labels 100, 200, i. Conductive surfaces with a self-adhesive layer, are fed via a label feeder.

Alternatively, an SMD placement machine can supply metal platelets of different thickness via a bulk material feed, the metal platelets preferably still not having a self-adhesive layer. Feeding of the metal platelets (eg copper pads) over a roll as a belted starting material is also possible.

The conductor surfaces preferably have an electrically and thermally highly conductive top side. For example, the labels may be copper and a self-adhesive bottom with e.g. Having polysiloxane adhesive. The self-adhesive underside can be used as a roll on backing paper.

Insulated conductor surfaces can also be glued to electrically conductive supports, since the conductor surfaces have already integrated the necessary functional insulation. However, the conductor surfaces can also be carried out without insulation, e.g. consist only of conductive layer and adhesive. These can then be equipped directly with a functional isolator. Substrates for this could be wood, plastic, glass or painted metal sheet. The materials used for the conductor surfaces (and also the carrier) can be designed both reflow-capable (temperature resistant to ...), as well as for low-melting solders or electrically conductive adhesives (wood substrate).

If sheet metal pads without their own self-adhesive layer are used as conductor surfaces, they can be supplied as bulk material from a certain strength (mechanical strength). Depending on the thermally necessary performance, they can be made with thicknesses between 0.05 mm and 0.5 mm. These platelets are then preferably carried out either without further layers or already have a suitable passivation (for example, HAL, chemical tin, OSP, ENIG, ...). The platelets are preferably placed directly on a self-adhesive surface by the SMD placement machine or the placement head grips the copper platelets and has an adhesive provided by a dispenser inside the placement machine on the underside. A suitable one Self-adhesive substrate may be, for example, a polyimide adhesive tape with a thickness between 10 and 50 .mu.m, in particular 25 .mu.m (for example, a CMC 70752). If this adhesive tape double-sided adhesive, it can be previously placed on a support element of different material. On the exposed up adhesive layer then the metal pads can be placed.

At the same time, the polyimide can assume the task of functional insulation and the normatively required isolation of typically 2000V AC RMS. If the placement of the layout pads on an electrically insulating support is planned, such. a painted sheet, then the conductor surfaces can be glued without an insulating film. For this purpose, the adhesive can be doctored, for example using a stencil printer with a suitable template on the carrier. As a result, adhesive deposits are generated precisely at the points and with the geometry, where in a second step, the metal pads are placed with the SMD placement machine. After completion of the electronic printed circuit board usually a reflow soldering process is necessary, are particularly suitable adhesives that are thermally cured.

FIG. 3 shows a plan view of an LED module 300. The LED module comprises a support member 310, on which three conductor surfaces 320 are arranged. Between the conductor surfaces 320 are LEDs 340 whose terminals 330 are soldered to the conductor surfaces 320.

FIG. 4 shows a side view of an LED module 400. The LED module 400 includes a support member 410, which also serves as a housing of the LED module. Applied to the carrier element is a full-surface dielectric 420. On this is a conductor surface 440 with a self-adhesive layer 430 attached. On the conductor surface 440, an LED 460 is attached to a terminal 450, wherein the terminal 450 is soldered to the conductor surface 440.

The conductor surfaces can be formed so that they can serve as a terminal for a wire via a hole in the substrate (back wiring). Or the conductor surfaces are shaped so that they replace an assembly-side clamp.

Thus, in a simple manner, it is also possible, as an alternative, to produce longer conductor tracks (which are otherwise impossible with this technology), which the wiring robot introduces. This also parallel circuits of LED chains can be realized.

The realization that layouts of LED applications can be reduced to a few geometric forms of the conductor surfaces makes it possible to create a layout with an SMD placement machine.

In the case described here, it is a matter of simplifying the layout to the absolute minimum, in order then to be able to produce layouts on an order-related basis using commercially available machines. The layout can be formed from a limited number of pieces of copper puzzle pieces, which are arranged freely combined.

The degrees of freedom regarding the choice of material and the cost of materials are great. If it is a plastic light can be dispensed with additional insulation that goes beyond a functional insulation. For thermally uncritical applications copper-clad labels can be used as solder pads and thus the costs are reduced. These if it is a thermally critical application or if a high cycle life is required, the described copper pads with a thickness of 0.070 mm to 0.5 mm can be used. The length of the circuit board is not limited by the technology. The pads, which can be held in different geometries, can be flexibly combined and thus the length and width of the PCBs and the number of LEDs and their arrangement (depending on available Padgeometrien) can be freely selected. This lowers the storage costs, as only unprocessed input material is stored.

LIST OF REFERENCE NUMBERS

100

conductor surface

110

Area with solder mask

120

Area with bare copper surface

200

conductor surface

210

self-adhesive layer

220

dielectric

230

copper

240

solder resist

300

LED module

310

support element

320

conductor surfaces

330

connection

340

LED

400

LED module

410

support element

420

dielectric

430

Self-adhesive layer

440

conductor surface

450

connection

460

LED

Claims (14)

A method of manufacturing an LED module, the method comprising: - Attaching conductor surfaces with a self-adhesive layer on a support element, and - fixing an LED on the conductor surfaces, wherein the fixing of the conductor surfaces is performed by an SMD placement machine. The method of claim 1, wherein attaching the conductor surfaces comprises applying the self-adhesive layer to the conductor surfaces and then attaching the conductor surface with the self-adhesive layer to the support member. The method of claim 1, wherein attaching the conductor surfaces comprises applying the self-adhesive layer to the carrier member and then attaching the conductor surfaces to the carrier member. Method according to one of the preceding claims, wherein the conductor surfaces have a thickness between 0.07 mm and 0.7 mm. Method according to one of the preceding claims, wherein the length and width of the conductor surfaces are greater than the length and width of the LED. Method according to one of the preceding claims, wherein the self-adhesive layer polysiloxane adhesive, acrylate adhesive and / or a polyimide adhesive tape having a thickness of 5 microns to 100 microns, preferably a thickness of 10 microns to 50 microns. Method according to one of the preceding claims, further comprising: - Acquisition of dimensions of the conductor surfaces and based on the dimensions, calculating a placement of the conductor surfaces to realize a given layout. Method according to one of the preceding claims, further comprising that the SMD placement machine provides the conductor surfaces with the self-adhesive layer. Method according to one of the preceding claims, wherein the conductor surfaces are fed via a bulk material feed, a linear feed and / or a roll as taped starting material. Method according to one of the preceding claims, wherein the carrier element on the side facing the conductor surfaces is electrically conductive and the conductor surfaces have an insulating layer, wherein the insulating layer is preferably adjacent to the self-adhesive layer. Method according to one of the preceding claims, wherein the carrier element comprises a plate made of composite plastic, glass and / or sheet metal. Method according to one of the preceding claims, wherein the conductor surfaces comprise metal, in particular copper. LED module, manufacturable with the steps: - Attaching conductor surfaces with a self-adhesive layer on a support element, and - fixing an LED on the conductor surfaces, wherein the fixing of the conductor surfaces is performed by an SMD placement machine. The LED module of claim 13, wherein the circuit board is a housing of the LED module.

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